Electrical power generation on a vehicle

ABSTRACT

A vehicle comprising: a shift reactor ( 110 ) configured to: receive carbon monoxide produced by the vehicle; and process the received carbon monoxide to produce an output comprising hydrogen; and a fuel cell ( 112 ) coupled to the shift reactor ( 110 ) and configured to: receive the hydrogen from the shift reactor ( 110 ); and produce, using the received hydrogen, electricity for use on the vehicle.

FIELD OF THE INVENTION

The present invention relates to the generation of electrical power onboard a vehicle.

BACKGROUND

Many aircraft comprise an aircraft electrical system. Typically, anaircraft electrical system comprises a self-contained network ofcomponents that generate, distribute, utilise and store electricalenergy. The components of aircraft electrical systems that generateelectrical power are generally driven by an engine of the aircraft. Theuse of fuel cells on aircraft for providing electrical energy is known.

In a separate field to the field of electrical power generation, coolingsystems on aircraft are known. For example, an aircraft may include acooling air cycle and/or a vapour cycle refrigerant system. A vapourcycle refrigerant system utilises a liquid to provide cooling at variousloads on the aircraft.

SUMMARY OF THE INVENTION

In a first aspect, the present invention provides a vehicle comprising:a shift reactor configured to receive carbon monoxide produced by thevehicle, and process the received carbon monoxide to produce an outputcomprising hydrogen; and a fuel cell coupled to the shift reactor andconfigured to receive the hydrogen from the shift reactor, and produce,using the received hydrogen, electricity for use on the vehicle.

The shift reactor may be a water-gas shift reactor configured to performa water-gas shift reaction using the received carbon monoxide.

The vehicle may further comprise a fuel store configured to store afuel, and an engine configured to receive the fuel from the fuel store,and to combust the fuel. The carbon monoxide may be a product of theengine combusting the fuel. The shift reactor may be arranged to receivethe carbon monoxide from the engine.

The vehicle may further comprise: a fuel store configured to store afuel, the fuel comprising a hydrocarbon; and a fuel reformer coupled tothe fuel store and configured to receive an input comprising thehydrocarbon and process the received input to produce an outputcomprising the carbon monoxide. The shift reactor may be arranged toreceive the carbon monoxide from the fuel reformer. The output of thefuel reformer may further comprise hydrogen. The shift reactor may beconfigured to: receive the output of the fuel reformer from the fuelreformer; process the received output of the fuel reformer to reduce acarbon monoxide content of the output of the fuel reformer and toincrease a hydrogen content of the output of the fuel reformer, therebyproducing an output of the shift reactor; and send the output of theshift reactor to the fuel cell.

The fuel reformer may be a plasma fuel reformer or a plasmatron fuelreformer.

The vehicle may further comprise a mixer configured to: receive the fuelfrom the fuel store; receive steam; mix the received fuel and thereceived steam, thereby to produce a mixture; and provide the mixture tothe fuel reformer as the fuel reformer input.

The shift reactor may be further configured to receive steam, and toprocess the received carbon monoxide using the received steam.

The vehicle may further comprise a cooling system configured to providewater as a coolant to one or more entities on the vehicle, thereby toprovide cooling to the one or more entities, wherein the steam isproduced by evaporation of the water during the cooling.

The fuel cell may be further configured to produce, as a result ofproducing the electricity, a fuel cell output comprising water, andoutput the water for use by one or more entities on the vehicle, the oneor more entities being remote from the fuel cell.

The vehicle may further comprise a water extraction system configured toreceive the fuel cell output produced by the fuel cell, extract thewater from the fuel cell output, and provide the extracted water to theone or more entities remote from the fuel cell.

The vehicle may further comprise a cooling system configured to receivethe water produced by the fuel cell, and provide, to one or more vehiclesubsystems on the vehicle, the water as a coolant, thereby to cool theone or more vehicle subsystems.

The cooling system may be configured to provide the water as a coolantto the fuel cell, thereby cooling the fuel cell.

The vehicle may be an aircraft. The fuel may be an aviation fuel. Thefuel may comprise C₆-₁₆ hydrocarbons. The fuel may comprise keroseneand/or naphtha.

In a further aspect, the present invention provides a method ofgenerating electricity on a vehicle. The method comprises: receiving, bya shift reactor on the vehicle, carbon monoxide produced by the vehicle;processing, by the shift reactor, the received carbon monoxide toproduce an output comprising hydrogen; receiving, by a fuel cell on thevehicle, the hydrogen produced by the shift reactor; and producing, bythe fuel cell, using the received hydrogen, electricity for use on thevehicle.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of an example aircraft; and

FIG. 2 is a process flow chart showing certain steps of a methodperformed by the aircraft.

DETAILED DESCRIPTION

FIG. 1 is a schematic illustration of an example aircraft 100 in whichan embodiment of an electrical power generation and cooling system isimplemented.

In this embodiment, the aircraft 100 is a manned aircraft.

The aircraft 100 comprises an engine 102, a fuel store 104, a mixer 106,a fuel reformer 108, a shift reactor 110, a fuel cell 112, electricalsubsystems 114, a water extraction system 116, a cooling system 118,aircraft subsystems 120, and a steam outlet 122.

In this embodiment, the engine 102 is a gas turbine engine configured tolo combust aircraft fuel (i.e. aviation fuel) to provide thrust for theaircraft 100. The engine 102 comprises an inlet. The inlet of the engine102 is coupled to the fuel store 104 via a first conduit 124. The firstconduit 124 is a fuel supply line. The engine 102 further comprises anoutlet (not shown) via which waste gases are expelled from an exhaust ofthe aircraft 100.

In this embodiment, the engine 102 does not generate any electricalpower on the aircraft 100. In other words, no electrical power isgenerated on the aircraft using a mechanical or pneumatic offtake fromthe gas turbine engine. For example, a mechanical output of the engine102 is not used (e.g. by a conventional gearbox driven system) togenerate electricity on the aircraft 100. Also for example, the exhaustgases from the engine 102 do not drive an electrical power generationsystem. In this embodiment, the aircraft 100 does not include any enginedriven electrical power generation systems.

In this embodiment, the fuel store 104 comprises one or more fuel tanksfor storing aircraft fuel. The fuel store 104 may further comprisemonitoring systems, such as fuel level, temperature and/or pressuresensors. The fuel store 104 may further comprise fuel distributionsystems, such as fuel pumps and supply lines. The fuel store 104comprises a first outlet and a second outlet. As described in moredetail later below with reference to FIG. 2, the fuel store 104 isconfigured to output aircraft fuel from its first and second outlets.The first outlet of the fuel store 104 is coupled to the engine 102 viathe first conduit 124. The second outlet of the fuel store 104 iscoupled to the mixer 106 via a second conduit 126. The second conduit126 is a fuel supply line.

In this embodiment, the aircraft fuel stored and distributed by the fuelstore 104 is jet fuel comprising kerosene and/or naphtha (e.g. Jet A,Jet A-1 or Jet B).

In this embodiment, the mixer 106 comprises a first inlet, a secondinlet, and an outlet. The first inlet of the mixer 106 is coupled to thesecond conduit 126. The second inlet of the mixer 106 is coupled to athird conduit 128. The third conduit 128 is a pipe or tube. As describedin more detail later below with reference to FIG. 2, the mixer 106 isconfigured to mix fluids received at its first and second inlets to forma mixture, and to output the mixture from its outlet. The outlet of themixer 106 is coupled to a fourth conduit 130. The fourth conduit 130 isa pipe or tube.

In this embodiment, the fuel reformer 108 is a plasma fuel reformer. Thefuel reformer 108 comprises an inlet and an outlet. The inlet of thefuel reformer 108 is coupled to the fourth conduit 130. As described inmore detail later below with reference to FIG. 2, the fuel reformer 108is configured to process fluid received at its inlet, and to outputprocessed fluid from its outlet. The outlet of the fuel reformer 108 iscoupled to a fifth conduit 132. The fifth conduit 132 is a pipe or tube.

In this embodiment, the shift reactor 110 is a water-gas shift reactor.The shift reactor 110 comprises a first inlet, a second inlet, and anoutlet. The first inlet of the shift reactor 110 is coupled to the fifthconduit 132. The second inlet of the shift reactor 110 is coupled to asixth conduit 134. The sixth conduit 134 is a pipe or tube. As describedin more detail later below with reference to FIG. 2, the shift reactor110 is configured to perform a water-gas shift reaction using fluidsreceived at its first and second inlets, and to output the resultingfluid from its outlet. The outlet of the shift reactor 110 is coupled toa seventh conduit 136. The seventh conduit 136 is a pipe or tube.

In this embodiment, the fuel cell 112 is a Proton Exchange Membrane(PEM) fuel cell. The fuel cell 112 comprises a fluid inlet, a fluidoutlet, and an electrical outlet. The fluid inlet of the fuel cell 112is coupled to the seventh conduit 136. As described in more detail laterbelow with reference to FIG. 2, the fuel cell 112 is configured togenerate electricity using hydrogen fuel received at its fluid inlet,and to output the generated electricity at its electrical outlet. Theelectrical outlet of the fuel cell is coupled to an electricalconnection 138. The fuel cell 112 is further configured to output, atthe fluid outlet of the fuel cell 112, fluids produced as a result ofgenerating electricity (e.g. by-products of the electricity generation).The fluid outlet of the fuel cell 112 is coupled to an eighth conduit140. The eighth conduit 140 is a pipe or tube.

In this embodiment, all electrical power generation on the aircraft 100is performed by the fuel cell 112. The fuel cell 112 satisfies allelectrical demand on the aircraft 100 by the electrical subsystems 114.

In this embodiment, the electrical subsystems 114 are aircraftsubsystems that consume electrical power, i.e. electrical loads. Theelectrical subsystems 114 may include, but are not limited to, a missionsystem, a navigation system, an avionics system, a fuel system, and anenvironmental control system. The electrical subsystems 114 areelectrically coupled to the electrical connection 138. The electricalsubsystems 114 may include some or all of the aircraft subsystems 120.

In this embodiment, the water extraction system 116 (i.e. a waterextractor) may be any appropriate water extraction system, including butnot limited to a steam cleaning system, a steam cooling system, aturbine water extractor, or a coalescer-based water extractor. The waterextraction system 116 comprises an inlet and an outlet. The inlet of thewater extraction system 116 is coupled to the eighth conduit 140. Asdescribed in more detail later below with reference to FIG. 2, the waterextraction system 116 is configured to extract water from fluid receivedat its inlet, and to output extracted water from its outlet. The outletof the water extraction system 116 is coupled to a ninth conduit 142.The ninth conduit 142 is a pipe or tube. In this embodiment, the waterextraction system 116 further comprises a further outlet (not shown inthe Figures) for exhaust gases from which the water has been extracted.These exhaust gasses may be expelled from the aircraft.

In this embodiment, the cooling system 118 is an evaporative coolingsystem that uses water as a coolant, i.e. a water-based cooling system.The cooling system 118 comprises an inlet and an outlet. The inlet ofthe cooling system 118 is coupled to the ninth conduit 142. The outletof the cooling system 118 is coupled to a tenth conduit 144. The tenthconduit 144 comprises pipes or tubes. In this embodiment, the tenthconduit 144 defines two fluid flow paths, in particular a first fluidflow path which travels through or proximate to the fuel cell 112, and asecond fluid flow path which travels through or proximate to theaircraft subsystems 120. As described in more detail later below withreference to FIG. 2, the cooling system 118 is configured to receiverelatively cool water at its inlet, and pump that relatively cool waterout of its output along the tenth conduit 144, thereby to providecooling to the fuel cell 144 and the aircraft subsystems 120. Thus, inthis embodiment the cooling system 118 is a pump configured to pumpcoolant water to other aircraft systems. In some embodiments, thecooling system 118 comprises means for reducing the temperature of thecoolant water prior to that coolant water being pumped by the coolantsystem 118 to other aircraft systems, for example one or more heatexchangers arranged to transfer heat from the coolant water.

In this embodiment, the aircraft subsystems 120 are aircraft subsystemsthat generate heat in operation. The aircraft subsystems 120 may benefitfrom cooling. The aircraft subsystems 120 may include, but are notlimited to, an environmental control system. The aircraft subsystems 120may include some or all of the electrical subsystems 114.

In this embodiment, the tenth conduit 144 extends from the coolingsystem 118, and then separates into a first branch and a second branchwhich pass through or proximate to the fuel cell 112 and the aircraftsubsystems 120 respectively. After passing through the or proximate tothe fuel cell 112 and the aircraft subsystems 120 respectively, thefirst and second branches of the tenth conduit 144 join together, andthen extend to the steam outlet 122. The third conduit 128 and sixthconduit 134 are each coupled to the tenth conduit 144 between the steamoutlet 122 and the section at which the first and second branches of thetenth conduit 144 join together.

In this embodiment, the steam outlet 122 is an opening at an externalsurface of the aircraft 100 from which fluid (e.g. steam) can beexpelled.

Apparatus for controlling the above arrangement, and controllingperformance of the method steps described later below, may be providedby configuring or adapting any suitable apparatus, for example one ormore computers or other processing apparatus or processors, and/orproviding additional modules. The apparatus may comprise a computer, anetwork of computers, or one or more processors, for implementinginstructions and using data, including instructions and data in the formof a computer program or plurality of computer programs stored in or ona machine readable storage medium such as computer memory, a computerdisk, ROM, PROM etc., or any combination of these or other storagemedia.

FIG. 2 is a process flow chart showing certain steps of an embodiment ofa method of operation of the electrical power generation and coolingsystem.

It should be noted that certain of the process steps depicted in theflowchart of FIG. 2 and described below may be omitted or such processsteps may be performed in differing order to that presented above andshown in FIG. 2. Furthermore, although all the process steps have, forconvenience and ease of understanding, been depicted as discretetemporally-sequential steps, nevertheless some of the process steps mayin fact be performed simultaneously or at least overlapping to someextent temporally.

At step s1, the fuel store 104 pumps aircraft fuel stored therein to theengine 102. The aircraft fuel is sent from the fuel store 104 to theengine 102 via the first conduit 124.

At step s2, the engine 102 combusts the aircraft fuel received from thefuel store 104 to generate thrust for the aircraft 100. In thisembodiment, waste gases from the combustion process performed by theengine 102 are expelled from the aircraft 100 via an aircraft exhaust.

At step s3, the fuel store 104 pumps aircraft fuel stored therein to themixer 106. The aircraft fuel is sent from the fuel store 104 to themixer 106 via the second conduit 126. The mixer 106 receives theaircraft fuel at its first inlet.

A temperature of the aircraft fuel received by the mixer 106 may bedependent on environmental conditions in which the aircraft 100 isoperating. Typically, the aircraft fuel is received by the mixer 106 inliquid form, having a temperature in the range of about −40° C. to about70° C.

At step s4, the mixer 106 receives steam at its second inlet from thethird conduit 128.

In this embodiment, the steam received by the mixer 106 via the thirdconduit 128 is steam that results from water being used to cool the fuelcell 112 and/or the aircraft subsystems 120 (as described in more detaillater below at step s32) and which is pumped to the mixer 106, by thecooling system 118 via the tenth conduit 144 and the third conduit 128(as described in more detail later below at step s34).

In this embodiment, the steam received by the mixer 106 at step s4 has atemperature of at least about 100° C. (at standard pressure, i.e. atnominal conditions in the atmosphere at sea level). In some embodiments,this steam may have a different temperature. For example, in someembodiments (e.g. embodiments in which the aircraft is operating at highaltitude, i.e. relatively low pressure compared to atmospheric pressureat sea level), this steam may have a temperature of less than about 100°C., e.g. between 90° C. and less than 100° C., or between 80° C. and 90°C., or between 70° C. and 80° C., or less than 70° C. Also, in someembodiments, this steam may have a temperature of more than about 100°C., e.g. more than 110° C., more than 120° C., more than 130° C., morethan 140° C., or more than 150° C.

At step s6, the mixer 106 mixes together the received aircraft fuel andsteam, thereby vaporising the aircraft fuel.

Vaporisation of the aircraft fuel, i.e. converting the aircraft fuelinto gaseous form, advantageously tends to facilitate fuel reforming bythe fuel reformer 108.

At step s8, the mixer 106 sends the gaseous mixture of aircraft fuel andsteam to the fuel reformer 108 via the fourth conduit 130. The fuelreformer 108 receives the gaseous mixture of aircraft fuel and steam atits inlet.

At step s10, the fuel reformer 108 processes the received gaseousmixture of aircraft fuel and steam to produce hydrogen.

In particular, in this embodiment, the fuel reformer 108 creates acontinuous plasma in a chamber. This chamber is then filled with thegaseous aircraft fuel (which in this embodiment comprises kerosenevapour) and air, whereby the aircraft fuel dissociates to create ahydrogen-rich gas. This hydrogen-rich gas comprises hydrogen gas andcarbon monoxide. The hydrogen-rich gas may comprise approximately 20%hydrogen gas (for example, about 18, 19, 20, 21 or 22% hydrogen). Thehydrogen-rich gas may comprise approximately 20% carbon monoxide (forexample, about 18, 19, 20, 21 or 22% carbon monoxide). The hydrogen-richgas may include other gaseous products, for example carbon dioxide andnitrogen gas.

At step s12, the fuel reformer 108 sends the hydrogen-rich gas to theshift reactor 110 via the fifth conduit 132. The shift reactor 110receives the hydrogen-rich gas at its first inlet.

At step s14, the shift reactor 110 receives steam at its second inletfrom the sixth conduit 134.

In this embodiment, the steam received by the shift reactor 110 via thesixth conduit 134 is steam that results from water being used to coolthe fuel cell 112 and/or the aircraft subsystems 120 (as described inmore detail later below at step s32) and which is pumped to the shiftreactor 110, by the cooling system 144, via the tenth conduit 144 andthe sixth conduit 134 (as described in more detail later below at steps34).

In this embodiment, the steam received by the shift reactor 110 at steps14 has a temperature of at least about 100° C. (at standard pressure,i.e. at nominal conditions in the atmosphere at sea level). In someembodiments, this steam may have a different temperature. For example,in some embodiments (e.g. embodiments in which the aircraft is operatingat high altitude, i.e. relatively low pressure compared to atmosphericpressure at sea level), this steam may have a temperature of less thanabout 100° C., e.g. between 90° C. and less than 100° C., or between 80°C. and 90° C., or between 70° C. and 80° C., or less than 70° C. Also,in some embodiments, this steam may have a temperature of more thanabout 100° C., e.g. more than 110° C., more than 120° C., more than 130°C., more than 140° C., or more than 150° C.

At step s16, the shift reactor 110 processes the received hydrogen-richgas and steam so as to effect a water-gas shift reaction.

In particular, in this embodiment, the shift reactor 110 causes thecarbon monoxide present in the received hydrogen-rich gas to react withthe received steam (i.e. water vapour) to form carbon dioxide andhydrogen gas. Thus, advantageously, the proportion of hydrogen in thehydrogen-rich gas tends to be increased, while the proportion of carbonmonoxide in the hydrogen-rich gas tends to be decreased. For example,the proportion of hydrogen gas in the hydrogen-rich gas may be increasedto be more than about 20%, e.g. at least 21%, at least 22%, at least23%, at least 24%, at least 25%, at least 26%, at least 27%, at least28%, at least 29%, at least 30%, at least 35%, or at least 40%. Also,for example, the proportion of carbon monoxide in the hydrogen-rich gasmay be decreased to be less than about 20%, e.g. at most 19%, at most18%, at most 17%, at most 16%, at most 15%, at most 14%, at most 13%, atmost 12%, at most 11%, at most 10%, at most 5%, at most 3%, at most 2%,or at most 1%.

At step s18, the shift reactor 110 sends its gaseous output (i.e. thehydrogen-rich having increased hydrogen gas content as a result ofundergoing the water-gas shift reaction) to the fuel cell 112 via theseventh conduit 136. The fuel cell 112 receives the hydrogen-rich gas atits inlet.

At step s20, the fuel cell 112 converts the hydrogen gas (comprised inthe received hydrogen-rich gas) into direct current (DC) electricitythrough a chemical reaction of positively charged hydrogen ions withoxygen from a received air supply.

Advantageously, the water-gas shift reaction performed by the shiftreactor 110 at step s16 tends to increase the proportion of hydrogen inthe hydrogen-rich gas received by the fuel cell 112. Thus, the amount ofhydrogen fuel for the fuel cell 112 tends to be increased. Thus, thefuel cell 112 tends to be able to generate more electrical power.

Furthermore, the fuel cell 112 may comprise a catalyst at either or bothof its anode and cathode. For example, the fuel cell 112 may comprise aplatinum catalyst at its anode that causes or facilitates the hydrogengas to split into positive hydrogen ions and electrons. Carbon monoxidemay detrimentally affect a catalyst of the fuel cell 112. The water-gasshift reaction performed by the shift reactor 110 at step s16 tends todecrease the proportion of carbon monoxide in the hydrogen-rich gasreceived by the fuel cell 112. Thus, a life of the fuel celladvantageously tends to be improved.

In this embodiment, a by-product of the fuel cell 112 converting thehydrogen gas into DC electricity is water, which may be in the form ofwater droplets dispersed within an exhaust gas (e.g. air). Typically,the exhaust gas from the fuel cell 112 including the water droplets isabout 60° C. to about 80° C. (for example, about 60, 65, 70, 75 or 80°C.). In some embodiments, the water by-product of the fuel cell 112comprises water vapour.

At step s22, the fuel cell 112 provides the generated electrical powerto the electrical subsystems 114 via the electrical connection 138. Theelectrical subsystems 114 consume the received electrical power.

In some embodiments, one or more or the fuel store 104, the mixer 106,the fuel reformer 108, the shift reactor 110, the water extractionsystem 116, the cooling system 118, and the aircraft subsystems 120 are,or may include, electrically driven apparatuses or systems, which may bepowered by electricity generated by the fuel cell 112. For example, thefuel reformer 108 may be an electrically driven fuel reformer powered byelectrical power received from the fuel cell 112.

At step s24, the fuel cell 112 sends its exhaust gas, including thewater by-product, produced at step s20 to the water extraction system116 via the outlet of the fuel cell 112 and the eighth conduit 140. Thewater extraction system 116 receives the exhaust gas at its inlet.

At step s26, the water extraction system 116 extracts water from thefuel cell exhaust gas received from the fuel cell 112. Any appropriatewater extraction process may be used to extract water from the fuel cellexhaust gas, for example a steam cleaning process, a steam coolingprocess, a process of extracting water from the exhaust gas viacentrifugal force, and/or a coalescence process.

At step s28, the water extraction system 116 sends the extracted waterto the cooling system 118 via the ninth conduit 142. The water sent fromthe water extraction system 116 to the cooling system 118 may, forexample, be in the form of a liquid, or may be in the form of waterdroplets dispersed within a gas. The water sent from the waterextraction system 116 to the cooling system 118 may have a temperatureof, for example, about 60° C. to about 80° C. (for example, about 60,65, 70, 75 or 80° C.) or less than about 60° C. (for example between 55°C. and 60° C., between 50° C. and 55° C., or between 40° C. and 50° C.).The cooling system 118 receives the water at its input.

At step s30, the cooling system 118 pumps the received water from itsoutlet, to the fuel cell 112 and aircraft subsystems 120 via the tenthconduit 144. At this stage, the water could be considered a watercoolant.

At step s32, the water flowing through the portion of the tenth conduit144 that passes through or proximate to the fuel cell 112 cools the fuelcell 112. In particular, relatively cool water (i.e. the water sent fromthe water extraction system which may have a temperature of about 60° C.to about 80° C. or less than about 60° C.) flowing through or proximateto the fuel cell 112 absorbs heat from the fuel cell 122. In thisembodiment, this relatively cool water is vaporised as a result of beingheated by the fuel cell 112.

The fuel cell 112 may include, or be located proximate to, a heatexchanger arranged to effect heat transfer between the fuel cell 112 andthe water coolant in the tenth conduit 144.

Advantageously, the cooling of the fuel cell 112 by the water coolantflowing through the tenth conduit 144 tends to reduce or eliminate thelikelihood of the fuel cell 112 overheating. Thus, damage to the fuelcell 112 caused by excessive heat tends to be reduced. Furthermore, aneed for other cooling systems on the aircraft 100 may be reduced, thusreducing weight of the aircraft 100.

At step s32, the water flowing through the portion of the tenth conduit144 that passes through or proximate to the aircraft subsystems 120cools the aircraft subsystems 120. In particular, relatively cool waterflowing through or proximate to the aircraft subsystems 120 absorbs heatfrom the aircraft subsystems 120. In this embodiment, this relativelycool water is vaporised as a result of being heated by the aircraftsubsystems 120.

lo One or more of the aircraft subsystems 120 may include, or be locatedproximate to, a heat exchanger arranged to effect heat transfer betweenthe aircraft subsystems 120 and the water coolant in the tenth conduit144.

Advantageously, the cooling of the aircraft subsystems 120 (a vehiclesubsystem) by the water coolant flowing through the tenth conduit 144tends to reduce or eliminate the likelihood of the aircraft subsystems120 overheating. Thus, damage to the aircraft subsystems 120 caused byexcessive heat tends to be reduced. Furthermore, a need for othercooling systems on the aircraft 100 may be reduced. Furthermore, theoperational efficiency of one or more of the aircraft subsystems 120 maybe improved as a result of the cooling.

At step s34, the cooling system 118 pumps the evaporated coolant water(i.e. steam) produced by cooling the fuel cell 112 and the aircraftsubsystems 120 (at steps s30 and s32 respectively) along the tenthconduit 144. The steam produced by cooling the fuel cell 112 and theaircraft subsystems 120 may have a temperature of at least about 100° C.(at standard pressure, i.e. at nominal conditions in the atmosphere atsea level). In some embodiments, this steam may have a differenttemperature. For example, in some embodiments (e.g. embodiments in whichthe aircraft is operating at high altitude, i.e. relatively low pressurecompared to atmospheric pressure at sea level), this steam may have atemperature of less than about 100° C., e.g. between 90° C. and lessthan 100° C., or between 80° C. and 90° C., or between 70° C. and 80°C., or less than 70° C. Also, in some embodiments, this steam may have atemperature of more than about 100° C., e.g. more than 110° C., morethan 120° C., more than 130° C., more than 140° C., or more than 150° C.

In this embodiment, a proportion of the steam is pumped from the fuelcell 112 and/or the aircraft subsystems 120, along the tenth conduit144, and then along the sixth conduit 134 to the shift reactor 110. Theshift reactor 110 receives steam at its second inlet from the sixthconduit 134, as performed at step s14 above.

In this embodiment, a proportion of the steam is pumped from the fuelcell 112 and/or the aircraft subsystems 120, along the tenth conduit144, and then along the fourth conduit 128 to the mixer 106. The mixer106 receives steam at its second inlet from the fourth conduit 128, asperformed at step s4 above.

In this embodiment, a proportion of the steam is pumped from the fuelcell 112 and/or the aircraft subsystems 120, along the tenth conduit 144to the steam outlet 122. This steam is then expelled from the aircraft100 via the steam outlet 122.

In some embodiments, the fourth conduit 128, the sixth conduit 134,and/or the tenth conduit 144 comprises one or more valves forcontrolling the flow of steam.

Thus, an embodiment of a method of operation of the electrical powergeneration and cooling system is provided.

The water by-product produced by the fuel cell tends to be ultra-pure,de-ionised water having little or no mineral content. Thus,advantageously, when this water is evaporated to provide cooling to thefuel cell and/or aircraft subsystems, little or no fouling of theconduits etc. occurs. In some embodiments, the water by-product producedby the fuel cell contains total dissolved solids of less than or equalto about 10 mg/litre.

Advantageously, the water by-product produced by the fuel cell is aneffective coolant. The water has good heat absorption qualities and heatcarrying capacity. The water coolant tends to be non-polluting,non-toxic, and non-flammable. Furthermore, the water coolant tends to beless corrosive to component parts of the system compared to conventionalcoolants.

Advantageously, the operating temperature of the PEM fuel cell tends tobe around 60° C. to 80° C. This relatively low operating temperaturetends to provide for improved safety on board the aircraft. Furthermore,this relatively low operating temperature of the fuel cell tends toprovide that the water by-product produced by the fuel cell is at around60° C. to 80° C. This relatively low water temperature advantageouslytends to facilitate water extraction by the water extraction system,compared to water being at higher temperatures.

Advantageously, cooling is provided on the aircraft using a by-productof the fuel cell generating electricity (i.e. the water produced by thefuel cell). This water by-product of the fuel cell may otherwise bewasted. Furthermore, the water coolant is produced on the aircraft inoperation. This tends to allow for the aircraft to carry reduced amountof other coolants or other water.

Advantageously, hydrogen fuel for the fuel cell, and water coolant foruse by the cooling system, is produced on the aircraft from the aircraftjet fuel. Thus, use of additional stores of hydrogen fuel and/or watercoolant on the aircraft, and associated distribution systems and supplylines, tend to be avoided. This tends to reduce aircraft weight.Furthermore, aircraft refuelling tends to be facilitated, as only asingle type of consumable fuel (i.e. jet fuel) is used by the aircraft.This tends to be particularly advantageous in embodiments in which theaircraft is refuelled via air-to-air refuelling.

The mixer, fuel reformer, and shift reactor advantageously tend torecover hydrogen from the water by-product of the fuel cell. In otherwords, the mixer, fuel reformer, and shift reactor advantageously tendto recover hydrogen previously used by the fuel cell.

The shift reactor advantageously tends to reduce the carbon monoxidecontent of the output of the fuel reformer. Thus, carbon monoxidecontent of the hydrogen fuel supply to the fuel cell tends to bereduced. This tends to result in improved life of the fuel cell.Furthermore, carbon monoxide emission of the aircraft may be reduced.

Conventionally, many aircraft comprise engine driven electrical powergeneration systems. For example, a conventional aircraft may include oneor more turbine based auxiliary power units (APUs). Conventionalaircraft may comprise electricity generators that are driven by bleedair extracted from the aircraft engines. In contrast, in the abovedescribed embodiments, the aircraft does not include any engine drivenelectrical power generation systems and the engine does not generate anyelectrical power on the aircraft. Instead, all electrical power on theaircraft is generated by the fuel cell, i.e. the fuel cell satisfies allelectrical loads on the aircraft. In some embodiments, one or morebatteries and/or other power storage or generation devices may beimplemented on the aircraft to provide electrical power, for example inaddition to the fuel cell. Advantageously, the fuel cell tends toprovide more efficient electricity generation compared to an enginedriven electrical power generator. For example, the fuel cell may be atleast 50%±5% efficient at electricity generation, while a conventionalgearbox driven electrical power generator may be ˜18% efficient atelectricity generation. Furthermore, by avoiding use of an engine drivenelectrical power generator, it tends to be possible to omit the enginedriven electrical power generator and associated apparatus (such as anengine radial shaft, gearboxes, and secondary power sources) from theaircraft, thereby reducing aircraft weight. Furthermore, by avoiding useof an engine driven electrical power generator, fuel usage by theaircraft engine tends to be reduced, thus allowing the aircraft to carryless fuel, thereby reducing aircraft weight. Furthermore, the fuel cellgenerating substantially all electrical power on the aircraft tends toprovide that the fuel cell produces, as a by-product of generating theelectrical power, a sufficient amount of water for the cooling system toprovide effective cooling.

In the above embodiments, the electrical power generation and coolingsystem is implemented on a manned aircraft. However, in otherembodiments, the electrical power generation and cooling system isimplemented on a different entity. For example, the electrical powergeneration and cooling system may be implemented on an unmanned airvehicle, a land-based vehicle, a water-based vehicle, or in a building.

In the above embodiments, the engine is a gas turbine engine. However,in other embodiments, the engine is a different type of engine.

In the above embodiments, the fuel is jet fuel comprising keroseneand/or naphtha. However, in other embodiments the fuel is a differenttype of fuel for the engine, for example a jet biofuel. Generally, thefuel may be any type of hydrocarbon-based fuel, for example fuel thatcomprises C₆-₁₆ hydrocarbons.

In the above embodiments, the fuel reformer is a plasma fuel reformer.However, in other embodiments the fuel reformer is a different type offuel reformer such as a plasmatron fuel reformer.

In the above embodiments, the shift reactor is a water-gas shiftreactor. However, in other embodiments the shift reactor is a differenttype of shift reactor.

In the above embodiments, the fuel cell is a PEM fuel cell. However, inother embodiments the fuel cell is a different type of fuel cell otherthan a PEM fuel cell. For example, in some embodiments the fuel cell isa fuel cell, such as a solid oxide fuel cell, that tends not to besignificantly detrimentally effected by the presence of carbon monoxidein the fuel cell fuel.

In the above embodiments, the electrical power generation and coolingsystem comprises a shift reactor to reduce carbon monoxide content inthe fuel reformer output. In some embodiments, the electrical powergeneration and cooling system comprises a separator (e.g. a chemicalseparator, or carbon monoxide scrubber) in addition to the shiftreactor. The separator may be configured to process the fuel reformeroutput and separate hydrogen gas from carbon monoxide. The separator maybe considered a carbon monoxide reduction module. The separator may bearranged to send the separated hydrogen gas to the fuel cell, and toprevent or oppose the separated carbon monoxide being sent to the fuelcell.

In some embodiments, the electrical power generation and cooling systemfurther comprises one or more coolers to cool the water output by thefuel cell prior to that water being received by the cooling system. Forexample, a pre-cooler may be arranged between the fuel cell and thewater extractor to cool the water received by the water extractor. Thismay facilitate extraction of water by the water extractor.

In the above embodiments, unused steam is expelled from the steam outletof the aircraft. However, in other embodiments, no steam is expelledfrom the aircraft, and substantially all water produced by the fuel cellis used and/or retained on the aircraft.

In the above embodiments, the mixer mixes steam with the aircraft fuelto vaporise the aircraft fuel. However, in other embodiments theaircraft fuel is lo vaporised in a different way, i.e. other than byusing steam. In some embodiments, the mixer is omitted.

In the above embodiments, the mixer receives steam from the coolingsystem, the steam being produced by the coolant water being evaporatedwhen cooling the fuel cell and/or the aircraft subsystems. However, inother embodiments the mixer receives steam from a different source onthe aircraft.

In the above embodiments, the shift reactor reacts steam with the fuelreformer output. However, in other embodiments the shift reactorreceives and utilises water in a different state, e.g. in liquid form,instead of or in addition to steam.

In the above embodiments, the shift reactor receives steam from thecooling system, the steam being produced by the coolant water beingevaporated when cooling the fuel cell and/or the aircraft subsystems.However, in other embodiments the shift reactor receives steam from adifferent source on the aircraft.

In the above embodiments, the electrical power generation and coolingsystem comprises a water extractor and a cooling system. However, inother embodiments, one or both of the water extractor and the coolingsystem is omitted. For example, in some embodiments, water produced bythe fuel cell is not used for cooling. The water produced by the fuelcell may be used in a different way on the aircraft (e.g. stored, orused as drinking water for people on board the aircraft), or may beexpelled from the aircraft.

In the above embodiments, the one or more entities to which the cooledwater is provided are one or more aircraft subsystems. However, in otherembodiments, the one or more entities may be any vehicle subsystems, forexample in a land-based vehicle or a water-based vehicle.

In the above embodiments, the engine does not generate any electricalpower on the aircraft. However, in other embodiments, the aircraftincludes one or more engine driven electrical power generation systems.

What is claimed is:
 1. A vehicle comprising: a shift reactor configuredto: receive carbon monoxide produced by the vehicle; and process thereceived carbon monoxide to produce an output comprising hydrogen; and afuel cell coupled to the shift reactor and configured to: receive thehydrogen from the shift reactor; and produce, using the receivedhydrogen, electricity for use on the vehicle.
 2. The vehicle accordingto claim 1, wherein the shift reactor is a water-gas shift reactorconfigured to perform a water-gas shift reaction using the receivedcarbon monoxide.
 3. The vehicle according to claim 1, furthercomprising: a fuel store configured to store a fuel; an engineconfigured to receive the fuel from the fuel store, and to combust thefuel; wherein the carbon monoxide is a product of the engine combustingthe fuel; and the shift reactor is arranged to receive the carbonmonoxide from the engine.
 4. The vehicle according to claim 1, furthercomprising: a fuel store configured to store a fuel, the fuel comprisinga hydrocarbon; and a fuel reformer coupled to the fuel store andconfigured to: receive an input comprising the hydrocarbon; and processthe received input to produce an output comprising the carbon monoxide;wherein the shift reactor is arranged to receive the carbon monoxidefrom the fuel reformer.
 5. The vehicle according to claim 4, wherein:the output of the fuel reformer further comprises hydrogen; the shiftreactor is configured to: receive the output of the fuel reformer fromthe fuel reformer (108); process the received output of the fuelreformer to reduce a carbon monoxide content of the output of the fuelreformer and to increase a hydrogen content of the output of the fuelreformer, thereby producing an output of the shift reactor; and send theoutput of the shift reactor to the fuel cell.
 6. The vehicle accordingto claim 4, wherein the fuel reformer is a plasma fuel reformer or aplasmatron fuel reformer.
 7. The vehicle according to claim 4, furthercomprising: a mixer configured to: receive the fuel from the fuel store;receive steam; mix the received fuel and the received steam, thereby toproduce a mixture; and provide the mixture to the fuel reformer as thefuel reformer input.
 8. The vehicle according to claim 1, wherein theshift reactor is further configured to receive steam, and to process thereceived carbon monoxide using the received steam.
 9. The vehicleaccording to claim 7, further comprising a cooling system configured toprovide water as a coolant to one or more entities on the vehicle,thereby to provide cooling to the one or more entities, wherein thesteam is produced by evaporation of the water during the cooling. 10.The vehicle according to claim 1, wherein the fuel cell is furtherconfigured to: produce, as a result of producing the electricity, a fuelcell output comprising water; and output the water to one or moreentities on the vehicle, the one or more entities being remote from thefuel cell.
 11. The vehicle according to claim 10, further comprising awater extraction system configured to: receive the fuel cell outputproduced by the fuel cell; extract the water from the fuel cell output;and provide the extracted water to the one or more entities remote fromthe fuel cell.
 12. The vehicle according to claim 10, further comprisinga cooling system configured to: receive the water produced by the fuelcell; and provide, to one or more vehicle subsystems on the vehicle, thewater as a coolant, thereby to cool the one or more vehicle subsystems.13. The vehicle according to claim 12, wherein the cooling system isconfigured to provide the water as a coolant to the fuel cell, therebycooling the fuel cell.
 14. The vehicle according to claim 1, wherein thevehicle is an aircraft.
 15. A method of generating electricity on avehicle, the method comprising: receiving, by a shift reactor on thevehicle, carbon monoxide produced by the vehicle; processing, by theshift reactor, the received carbon monoxide to produce an outputcomprising hydrogen; receiving, by a fuel cell on the vehicle, thehydrogen produced by the shift reactor; and producing, by the fuel cell,using the received hydrogen, electricity for use on the vehicle.
 16. Thevehicle according to claim 8, further comprising a cooling systemconfigured to provide water as a coolant to one or more entities on thevehicle, thereby to provide cooling to the one or more entities, whereinthe steam is produced by evaporation of the water during the cooling.